Antihalation layer



Aug. 28, 1934. w. SCHNEIDER 1,971,430

' ANTIHALATION LAYER y I Filed April 30, 19:52

sappor'/ By Afforney Patented Aug. 28, 1934 PATENT OFFICE.v

AN'rmALA'rIoN LAYER Wilhelm Schneider, Dessau in Anhalt, Germany,

assgnor to Agfa Ansco Corporation, Binghamton, N. Y., a. corporation of New York VApplication April 30, 1932, Serial No. 608,518 In Germany May 8, 1931 Claims.

My presentinvention relates to the manufacture of anti-halation layers for photographic man terial and more particularly to anti-halation layers which present some advantages when vapplied 5 to photographic materials destined for the reversal process.- l

One of its objects is to provide an anti-halation layer which is easily removable in the reversal baths, while the film support is colored with a l l0 dye coveringthe gapsI of absorption of the removable anti-halation layer and giving at the same time an agreeable impression to the spectator of the finished material. Further objects Will be apparent from the detailed speciilcation following hereafter.

According to this invention the photographic material is provided with an anti-halation layer comprising colloidal silver, that is to say, silver in such a state that the single particles cannot be discerned with the microscope, and a binding agent. Such a layer of colloidal silver has the action of a light filter the spectral permeability of which depends upon the size of the colloidal silver particles. The larger the` particles the more the permeability will be shifted from the yellow to the green region of the spectrum. The size of the particles can be influenced by the addition of a suitable electrolyte, 'such as disodium phosphate, during or after the manufacture of the mixture of colloidal silver and binding agent, the addition of an electrolyte causing an increase in the size of the particles. I prefer to operate in such a manner that the anti-halation layer be permeable to the range from about 550 to '700 p4. In this case the support is dyed blue or violet, for instance lavender. As suitable dyes I mention light blue (Schultz, Farbstoitabellen 1923, Nr. 521), aniline blue` (Schultz, Farbstotabellen 1913, Nr. 521), violet B (Schultz Farbstofftabellen 1923, Nr. 517). A lavender color is obtainable by mixing a blue dye with rhodamin 3 B (Schultz, Farbstoiftabellen 1923, Nr. 574). Preferably a dye is selected which gives an agreeable impression to the spectator. As a binding agent for the colloidal silver layer I prefer gelatin but other binding agents, such as casein or the calcium salt of polyglucuronic acid likewise may be' Instead of the ,dyes which give an agreeable impression to the spectator of the finished photographic material dyes which do not give such an impression to the spectator likewise may be used, however, in this case the dyes must be removed 00 during the reversal developing process. These dyes may be incorporated in the same layer as the colloidal silver or they may be applied in a separate layer. Suitable dyes are, for instance, those whichare described in my copending application Serial Number, 586,966, led January 15, 1932.y In case of employing these dyes preferably an acid permanganate solution is used as reversal y developing bath instead of the acid blchromate bath. lThe gelatin or other binding material con- !0 The following examples serve to illustrate the I invention: A l

Example 1.-A solution of 25 grams of hydrazine sulfate in 500 grams of water is-added to a solution of 1000 grams of water grams of silver nitrate 200 grams of ammonia of 30 per cent strengt and 190 grams of gelatin 1 in the course of 1 hour at a temperature of 60 C. 85 Heating is then continued for further 45 minutes. Hereafter the solution is allowed to solidify, cut into small pieces and washed with water for about 1 to 2 hours. After having been molten the product is applied in the usual manner to a support 00 lwhich has been dyed with aniline blue. In case of a support made of nitrocellulose a solution of 5 to 10 grams of dyestufi in 100 parts of a. mixture of methanol and alcohol 4:1 is used and in the case of a support made of acetyl cellulose a solu- 96 tion of 5 to 1.0 grams of dyestufl ln 100 parts of a mixture of methanol and acetone 4:1 is used for dyeing the support.

Example 2.-50 per cent of a gelatin containing colloidal silver prepared according to Example 1 `100 and 50 per cent of gelatin containing the coupling product of 1.7-aminonaphthol and dianisldine are mixed and this mixture is applied in known manner as anti-halation layer. 'I'he gelatin containing the said coupling product is obtainable as follows. A solution of 50 to 100 parts by weight of gelatin in 800 parts by weight of water is mixed with 100 parts by weight of 116 molal solution of 1.7-aminonaphtho1 and 3 parts by weight of `sodium carbonate.` This mixture is brought to a temperature of about C. and there are added 100 parts by weight of 115 molal diazo solution of dianisidine. The resulting mass is allowed to solidify, cut in pieces, washed and molten and is then ready for use.

The accompanying drawing illustrates my invention and is in itself explanatory.` I do not intend to limit my invention thereto, other arrangements or combinations of the support, thev proper anti-halation layer and the light-sensitive emulsion layer being possible.

My invention is not limited to the foregoing examples or to the speciiic details given therein. Numerous other embodiments are possible, so, for instance, other dyes than those mentioned may be used, or dyes may be used which are soluble in the alkaline developer. I contemplate as included within my invention all such modifications as fall within the scope of the appended claims.

What I claim is:

1. A process for manufacturing anti-halation layers which comprises dissolving silver nitrate in an aqueous solution of a binding agent containing ammonia, precipitating the silver in colloidal form by adding a reducing agent, allowing the solution to solidify, reducing the solidiiied mass to small pieces, washing the pieces and preparing the anti-halation layer from this product.

2. A process for manufacturing anti-halation 'layers which comprises dissolving 100 parts by :hour at a temperature of 60 C., continuing heating for further minutes, causing then the solution to solidify, reducing the solidiiled mass to small pieces, washing the pieces for about 1-2 hours and producing the anti-halation'layer from the product thus obtained.

3. A photographic article comprising a light sensitive emulsion, a supportA for said emulsion and an anti-halation layer attached to said support comprising colloidal silver and a binding agent.

4. A photographic article comprising a light sensitive emulsion, a support for said emulsion and an anti-halation layer attached to said support, said anti-halationy layer being permeable to the wave lengths from about 550 to 700 pp. comprising colloidal silver and a binding agent.

5. A photographic article comprising a light sensitive emulsion, a support for said emulsion and an anti-halation layer attached to said support, said anti-halation layer beingl permeable .to wave lengths from about 550 to '100 mi comprising colloidal silver and a. binding agent, and said support being colored with a dye covering the gap of absorption of said anti-halation layer.

6.*-A `photographic article comprising a light sentitlve emulsion, a support for said'emulsion and an anti-halation layer attached to said support, said anti-halation layer being `permeable to wave lengths from about to 700 [la comprising colloidal silver and a binding agent, and said support being colored with a dye covering the gap of absorption of said anti-halaton layer, and constituting a permanent coloration suitable in projecting the finished film.

7. A photographic article comprising a light sensitive emulsion, a support for said emulsion and an anti-halation layer attached to said support, said anti-halation layer being permeable to wave lengths from about 550 to 700 up. comprising colloidal silver and a binding agent, and said support being dyed with a mixture of light blue and -rh'odamin 8. A photographic article comprising a light sensitive emulsion, a support for said emulsion and an anti-halation layer attached to said support comprising colloidal silver, a dye soluble in a photographic reversal bath, and a binding agent.

9. A photographic articlecompn'sing a light sensitive emulsion, a support for said emulsion and an anti-halation layer attached to said support comprising lcolloidal silver, the coupling product of lfl-aminonaphthol and dianisidine, and 'a binding agent.

10. A photographic article comprising a light sensitive emulsion, a support for said emulsion and an anti-halation layer attached to said support, said anti-halation layer being permeable to wavelengths from about 550 to 700 ya comprising colloidal silver and gelatin.

WILMLM SCHNEIDER. 

